docs: def _get_recurrence_model(input_model):
      """
      Returns the annual and cumulative recurrence rates predicted by the
      recurrence model
      """
      if not isinstance(input_model, (TruncatedGRMFD,
                                      EvenlyDiscretizedMFD,
                                      YoungsCoppersmith1985MFD)):
          raise ValueError('Recurrence model not recognised')
      # Get model annual occurrence rates
      annual_rates = input_model.get_annual_occurrence_rates()
      annual_rates = np.array([[val[0], val[1]] for val in annual_rates])
      # Get cumulative rates
      cumulative_rates = np.array([np.sum(annual_rates[iloc:, 1])
                                   for iloc in range(0, len(annual_rates), 1)])
      return annual_rates, cumulative_rates